High voltage switch



Sept 2, 1941- E. F. BALDwlN 2,254,560

HIGH VOLTGE SWITCH v l Filed sept. v26, 1938 5 sheets-shet 1 INVENToR.

ATTORNEYS. )g

` Sept. 2, 1941. F. BALDWIN HIGH VOLTAGE SWITCH Filed sept.. 26,A 1958 5sheets-sheet 2 TRA/VSP: Sec. ONE SIDE ONLY O u o) 'TRANS-R2 *ZT 05% 772ANaf: `)DRL INVENTOR.

ATToRNEY 5 sheets-Senz F INVENToR.

Y v u ATTORNEYS.

Sept 2, 1941- E. F. BALDWIN 2,254,560

HIGH VOLTAGE SWITCH Filed Sept. 26, 1938 5 Sheets-Sheet 5 I [Nsu/ A r/oNY 1-1 3 G. METAL @6) G37@ a A@ 9 i 21 39@ e) @6 @@"g Q@ Q ffl# 4 Q 4 cj@53- 44 J@ n Y f G) G) e 48 @1 e :49 G) 14 Q '14 @@vcaQQ@ Q Q lo e e @n ne e 56 Q .3a

1 l R FS) 15P f2 lfJ f) 75T/ 74 k 377* "71 ibi 72' v M L ,r r E l l *aiINVENTOR. ao @QM 121153. 87% wf BY Psi A-C- s ATTORNEYS- 'in apredetermined time.

Patented Sept. 2, 1941 UNITED STATES PATENT OFFICE HIGH VOLTAGE SWITCHEugene F. Baldwin, San Francisco, Calif.

Application September 26, 1938, Serial No. 231,686

l(Cl. o-11) 4 Claims.

My invention relates to high voltage switching systems, and moreparticularly to that type of systemV wherein a rotating switchcommutates high voltage for the purpose of producing progressiveillumination of electrical discharge tubes in signs or similar displays.

Among the objects of my invention are: To provide a high voltageswitching system for the progressive illumination of electricaldischarge tubes, such as used in what is known in the art as neon signs;to provide a high voltage switching system capable of progressivelyilluminating total lengths of luminous tubing beyond the maximum lengthcapable of being energized by a single transformer; to provide a unitaryenclosed high voltage switch; to provide a high voltage switchingsystem, progressively picking `up additional transformers as the lengthof tubing connected increases; to provide an automatic high voltageswitching system which is positively stabilized and which givessubstantially equal intensity of illumination at all steps alongluminous tubing as the illumination advances; to provide a high voltageswitching system for luminous tubes following standard underwriters codepractice; and to pr'ovide a simple and safe high voltage switchingsystem for luminous tubes.

Other objects of my invention will be apparent or will be specificallypointed out in the description forming a part of this specification, butI do not limit myself to the embodiment of the invention hereindescribed, as various forms may be adopted within the scope of theclaims.

This application is a continuation-impart of my prior co-pendingapplication entitled "High tension switch, Serial No. 132,28'7, filedMarch 22, 1937.

B'roadly, my invention comprises a rotating switch progressivelyilluminating, step by step in predetermined units of length, multiplebanks of luminous tubes, such as the tubes employing an .electricaldischarge in the monatomic gases, neon,

argon, krypton, helium, mercury vapor, etc., in such a manner thatprogressive illumination of a sign formed from such tubing exists fromthe inception of the illumination or the beginning point of the sign,thence forward in an orderly sequence to a complete focal point ofconclusion A dark period then is provided, following which therecreation of the sign copy is luminously enacted at a predeterminednumber of cycles per minute.

The present application describes a standardized switching -systemadapted to control progressive illumination up to approximately 2'10 of15 millimeter blue gaseous tubing, or the proportionate footageof othercolors in conventional use, calculated according to standard codepractice of millimeter sizes and gas resistance.

During one cycle of operation, the unit to be described provides for 119advance movements of progressive illumination, i. e., 119 single lettersin sequence, or, where straight-away borders or script letering areused, 119 units of length, the rapidity of the progressive illuminationbeing such as to denote continuous forward motion.

Referring to the drawings:`

Fig. 1 is a perspective view of the back of a preferred form of switchcasing, together with a schematic wiring diagram and representation ofthree tube banks.

Fig. 2 is a perspective view of the front of the casing showing certainjumper connections, a wiring diagram of the transformers, and certainconnections to the three tube banks. In this view of the front of thecasing the tubes have been rotated end for end to simplify the wiringdiagram, and therefore the direction of progression of illumination hasbeen reversed.

Fig. 3 is a longitudinal sectional view taken -through the axis of thehigh voltage switch Fig. 6 is a cross sectional view, taken as indicatedby the line 6 6 in Fig. 5.

Fig. '7 is a simplified wiring diagram showing the action of the switch.f

Fig. 8 is a plan view of the front of the switch, with a wiring diagramsuperimposed thereon to show primary circuit connections.

Fig. 9 is a plan view of the Contact face of the switch, showing theswitch arm, individual contacts, slip rings, a complete wiring diagramto the slip rings, and a partial wiring diagram of the tube banks. Inthis view the insulating ridges have been omitted for clarity ofillustration.

The drawings are substantially to scale.

For a better understanding of my switching system, a description willfirst be given of the high voltage switch, as shown in Figs. 1 and 2.

A foundation I 0 is provided, having brackets H fastened thereto andsupporting an extension block I2 molded integrally with a'contact plateI4the outside of which is shown in Fig. 2. On the outside of contactplate I4 are multiple receptacles l5 imbedded in raised ribs I6. Eachreceptacle I5 extends through contact plate I 4 to form an electricalcontact on the other side thereof, certain of these contacts beingcircular, certain of them being arcuate, and certain of them beingcomplete rings, as will be described later.

A cover is provided engaging the periphery 2| of the contact plate I4 tomake a tight seal therewith, thus leaving an interior space in which aswitch arm 22 may rotate, driven by central shaft 24 which in turn isrotated by motor 25 mounted on lugs 26 attached to cover 2U, through areduction gear 21. The cover is also provided with an external oilfilling pipe 23 and a drain plug at upper and lower levels,respectively. The switch arm will be described in detail later.

Referring now to Fig. 9 for the interior arrangement of contacts on theinterior surface 3| of contact plate I4, it will be seen that thecontact plate is provided with a completely blank segment 32 ofapproximately 40 of arc. At one side of this blank segment alined rowsof separate contact raised studs 33 begin. Studs in adjacent rows arecircularly positioned and the circles are separated by insulating ridges33 shown only in Fig. 3. In the embodiment described each row, at thebeginning, comprises ,ve separate contacts, each connected through tothe back of the plate and terminating in a receptacle I5. The rows arenot parallel or radial, but are alined tangentially to a circle drawnaround the axis of shaft 24. Similar rows continue around the plateuntil fifty-one contacts have been laid out, five in each of ninesuccessive rows 34, and four in the tenth row 35. From this point on,the outer circle of contacts becomes a continuous arcuate contact 36,continuing in the same radial position until the opposite edge of blanksegment 32 is reached. Ten rows 31 having four each of contact studs 33are then provided, and the next row 39 has only three studs 33, the next`tc the outer contact circle then being continued as an arcuate contact40 terminating at the same radius as arcuate Contact 36. Nine rows 4I ofthree each contacts follow, and the end row on the terminating radius isthen a single contact 42.

Immediately inside the rows of studs 33 is a complete slip ring 44separated from the studs by ridges 45 shown in section in Fig. 3, butomitted from Fig. 9. Still further toward the center of the plate arethree interrupted resistor rings 48, 41 and 4l, numbering from outsideinwardly, and a final complete inner ring 48. 49 inclusive are separatedfrom ring 44 by another series of ridges 45, also omitted from Fig. 9.

Switch arm 22 is of insulating material and carries two groups ofidentical brushes 50, the outer group 5| of six brushes being allconnected together by secondary jumper 52 and positioned at properradial distances to wipe studs 33, continuous contacts 36 and 40, andthe complete slip ring 44. An inner group 53 of four brushes, joined bya primary jumper 54, is positioned to wipe rings 4S to 49 inclusiveduring rotation of the arm. The details of each brush are shown in Figs.5 and 6.

A single piece of metal 55 is fastened across the extent of arm 22 byscrews 51. This metal is bent back upon itself to form a broad V 59,terminating on the other side of screws 51 in contact with itself.provided to regulate the distance of the point of the V from the arm.Thus, each brush 50 may separately flex to accommodate any unevenness Anadjustment screw\$0 'is Rings 46 to shown in Fig. 7 this switching isnot shown as in contact height. In practice, however, ver? littleunevenness oi.' this sort is encountered, because after all contactrings, segments and stud: are in place, the entire switch plate isplaced in a lathe and the metal portions faced off to a substantiallyuniform plane.

Having thus described the complete mechanism of the switch, I will nowdescribe the wiring set-up as used for multiple tube banks with multipletransformers.

Fig. '1 shows a simplified wiring diagram, which will be described firstin order to make the wiring diagram of the actual device easier tounderstand. In this simplified diagram only two tube banks are shownconnected. First tube bank Iis provided with the usual end electrodes 10and 1I and intermediate electrodes 12 equally or variably spaced alongthe extent of the tube. One end electrode 1| is connected directly tothe secondary 14 of transformer |T, and one end electrode of tube bank 2is connected to secondary 14 of transformer 2T. The first contact on theswitch is connected to the first intermediate electrode 12, and so onuntil the end of the tube is reached, where the opposite end electrodeIII is connected to the first continuous contact 3l. Arm 22, in thiscase, being shown as electrically conductive, is connected to both ofthe other sides of secondaries 14 of transformers IT and 2T. Thus, asarm 22 rotates the outer brush 3|) on arm 22 progressively wipes overthe contacts 33 and progressively illuminates, step by step, tube bankI. After the outer brush 50 has passed over all the contacts 33 it willthereafter ride on continuous contact 36 and tube I will remainilluminated. Continued movement of arm 22 will cause the next fourbrushes 50 to pick up the next inner circles of studs 35, these beingConnected to intermediate electrodes in tube bank 2 in order, until theend of that tube bank is reached, and so on for the number of tube banksprovided until all contact ceases, whereupon all energization of thetubing will cease and the transformers IT and 2T will be open-circuitedon the secondaries thereof.

In order, therefore, to prevent the voltage rising on open circuit, Iprefer to provide the primaries 15 of transformers IT and 2T with seriesresistors IR and 2R, and provide separate switching means so that whenthe transformers are energizing tubing the primary resistors for thosetransformers are out of circuit, but when the rotating arm passes offall contacts the resistors will be in the primary circuits, thusreducing the secondary voltage. In the schematic drawing beingautomatic. In the actual device, however, this switching is entirelyautomatic, as 'will be described later.

Referring directly `to Fig. 9 for the actual wiring diagram, tube-bank Ihas one end thereof connected to the secondary 14 of transformer |T.Tube bank 2 similarly has one end thereof connected to the secondary 14of transformer 2T. Tube bank 3 similarly has one end thereof connectedto the secondary 14 of transformer 37T. The other ends of thesecondaries of these three transformers are connected together withinextension I2 at receptacles I5T, and a single connection is .then madebetween the three receptacles IST and complete slip ring 44. which hasthe inner brush of the outer group 5| bearing againsty it, this brushbeing connected to the remaining five brushes oi' the outer group. Thus,the common side of all the transformers is connected to outer brushgroup BI at all times. Contact studs 38 in rows 34 are then connectedserially to intermediate electrodes 12 in tube bank I. and the oppositeend electrode 1li of tube bank I is then connected to outer continuouscontact 33. Similarly, intermediate electrodes of tube bank 2 areserially connected to studs 33 in rows 31 until the continuous contact40 is reached,

which connects to the opposite end electrode of tube bank 2. Theremaining studs 33 in rows 4I are then connected serially tointermediate contacts in tube bank 3, end contact 42 being connected tothe end electrode of tube bank 3, this latter electrode being the lastin the entire length of tubing. This comprises the complete secondarycircuit.

The primary circuit is as follows: The primaries 15 of transformers IT,2T and 3T are connected together at one end in primary receptacles I5Lon extension I2, and these connected receptacles are connected directlyto one side 80 of the A. C. supply line. The other side 8I`of the A. C.line goes to innermost annular slip ring 48. The remaining open ends ofthe three primaries are attached to receptacles I5P on extension I2 andthence divided, one branch passing through resistors IR, 2R and 3R. toresistor rings 46, 41 and 48 respectively. These resistor rings aredivided into two segments, one of which may be termed a resistor segmentand the other a shorting segment. IR connects to the shortest resistorsegment, 2R connects to a longer resistor segment, and 3R connects to astill longer resistor segment. The length of the resistor segmentscorresponds to the length of the arcuate extent of the three groups ofcontact rows 34, 31 and 4I, and these resistor segments are alsopositioned in such a manner that the resistors are in circuit onlyduring the times when the transformers are not being used. For example,

during the passage of the arm over rows 34, trans-y formers 2T and 3Tare not being used. As soon as rows 31 are reached, transformerI 3T isnot being used, and when the blank area is reached none of thetransformers is being used. The shorting segments, therefore, areconnected directly to receptacles I5P so that when the inner bank ofbrushes 52 rotates over the resistor segments, the resistors are cut inand out in accordance with the position of the arm on the stud rows.

In order that the switching arrangement may be made flexible, theconnections just described are made on the back of the contact plate I4by patch cords 82, as shown in Fig. 2. Likewise, the connections to thetube banks are made with removable connectors SIJ, as shown in Figs. 2and 3, so that they may be readily removed, changed, or the order ofprogression varied as desired. The

f resistors IR, I2R and 3R are preferably connected in the appropriatepatch cords 82, and/mounted on the outside of the contact plate I4 inclips 84.

The switching system of my invention has many advantages. For example,all switching is done on the common side of the transformers, or as maybe stated, at zero potential. Thus, there is never any difference ofpotential between high voltage switch brushes 50. The tangentialVarrangement of contacts causes a make potential equal only to thevoltage drop in the length of tubing between intermediate electrodes,inasmuch as a number/of the studs are in contact with group 5I at/thesame time. At the end of the illumination cycle when all the contactsare broken, all the resistors are thrown into the clr 40 continuouscontacts would be wasted.

5 have between them a long surface insulation due to the use of ridgeson the inside of the plate and completely enclosed receptaclesfon theoutside of the plate.

In practice, I prefer to rotate the switch arrn 10 to give seven cyclesper minute, one cycle every 81@ seconds, including a dark period of lsecond. It should also be notedthat there is only one moving part, andthat all electrical contact points, terminals and connections are eitherenclosed or are located below the surface level of the main insulatingstructure. Thus, when the usual high voltage cable is utilized no liveconductor is exposed on the outside of the device.

It will be noticed that in the device shown that the first tube bankwill handle fifty inter-- mediate electrodes, the second tube bankthirtynine intermediate electrodes, and the third tube bank twenty-sevenintermediate electrodes. However, it is to be understood that the samefootage may be handled in all banks by varying the spacing of theintermediate electrodes, or, if desired, the continuous contacts 36 and40 may lie-positioned in two additional outer rings, thus giving eachbank of studs the same numlber.

I prefer, however, and have found it more practical, to reduce thenumber of studs in succeed'- ing banks, because the preferred manner ofmaking the switch contact plate ls to mold it of insulatingmaterial inone piece, with all metallic portions inserted before molding. Thearrangement shown utilizes all the space available, whereasl if separateperipheral space were to be used for the continuous contacts, thatperipheral space Ibetween the beginning and end of these Thus, with thearrangement shown I am actually able to obtain two outer partial rows ofstuds within the same circular diameter.' If, however, it is desiredthat all tube banks have the same number of intermediate electrodes withthe same spacing therebetween, then it will be obvious to anyone skilledin the art, when patching in the tube connections, to leave outconnections to the two outer rows up to the beginning of f Ibothcontinuous contacts.

It will thus be seen that by the patching arrangement shown partially inFig.y 2, that I am able to obtain connections for almost any type ofsign desired, and that the switch itself as a 5 unit is adaptable formany sign and display designs without change thereof, except in the vouter circuit arrangements, as determined by j' patching into thereceptacles.

I claim:

l. .A rotary switch comprising a. contact plate of insulating materialprovided with a blank area. over a predetermined angular outer segmentthereof, a plurality of radially spaced circular rows of contractsconcentrically arranged in'said r plate around a central point on saidplate and occupying the remaining angular outer segment of said plate,at least one outer row having an initial portion of serially spacedcontacts beginning at one side of s aid [blank angular segment and aremaining continuous contact portion ending at the other side of saidblank angular segment and at least one inner row having serially spacedcontacts throughout, the serially spaced contacts in each circular rowbeing regularly staggered from those in an adjacent row to pro- 3.Apparatus in accordance with claim 1; wherein a circular ridge ofinsulating material is raised from said plate between each circular rowof contacts and wherein a plurality of simi lar circular ridges areprovided between said circular continuous contact and the inner rows ofthe remaining rows of contacts.

4. Apparatus in accordance with claim l, wherein all of said contactsare extended through said plates and terminate in a hollow socket on theback of said plate.

EUGENE F. BALDWIN.

